1. Add a "technical" section to the documentation, which describes how the src/*.pm.t files are compiled into the .php files for each theme. It took me quite some time to figure out that I couldn't just make changes to the .php files and have them persist.

Yeah, but variables are not always in the scope of functions that use them and so on. If you want to see what the various #s mean looks inside GLOBALS_HELP, which documents all global constants. The sql/*.tbl files identify the keys for used in various tables.

but those *.t files, arent they only used when compiling the theme? wouldn't it then be possible to define own "pseudo" constants, that when compiling the theme translates to the constante of choose to it's real value/string?